World's Greatest Detective: Genesis
by Katrina Castillo
Summary: It's been three years since the Batman first appeared to protect Manhattan, and he's grown a reputation within both the criminal underground and the legal system. Richard Castle, the man behind the mask, has started to feel the burden of living a double life. But when he crosses paths with Det. Beckett, he finds a new muse and begins to see just what the NYPD is capable of.


**IT'S STARTING! _World's Greatest Detective: Genesis_ is officially starting! In case you couldn't tell, I AM SO EXCITED! AND I HOPE YOU ARE TOO!**

**Ok, so as I've said before, _World's Greatest Detective: Genesis_ will cover seasons one and two of _Castle_. I have the general timeline of season one all figured out, and now I'm working on season two. I do ask that you all bear with me on this one; this part of the story requires a LOT of research which takes a lot of time. As some of you may know, I am taking summer classes at college which end next Saturday (8/9/14) and I will have only TWO weeks of vacation until I have to go back to college. Just know that updates will come. There may be one short hiatus between season one and two (maybe 1 or 2 weeks), but that's it. Nothing too bad.**

**Alright, enough talk. Let's read!**

**Disclaimer: Not mine. None of it. Just the crossover concept. Other than that, nothing. Zip. Zilch. It is not mine.**

* * *

_"Murder. Mystery. The macrabe. However the spell is cast, tonight we honor a master of the form and celebrate the launch of __Storm Fall__... Ladies and gentlemen, the master of the macrabe; Richard Castle!"_

_"Alison Tisdale. 24, grad student from NYU."_

_"Two shots to the chest. Small caliber."_

_"Does this look familiar to anyone?"_

_"You've seen this before? Where?"_

_"Don't you guys read?!"_

* * *

"You should have me committed," Castle muttered, coming to stand beside Alexis. The redhead looked up from her books, brows furrowed.

"For what?" she questioned. "The party?"

Castle took a sip of champagne before turning to Alexis. "Do you want to know why I killed off Derrick?" he asked. "There were no surprises, no more challenges. I knew exactly what was going to happen, every moment in every scene. Life is supposed to be full of adventure and surprises."

"And Derrick Storm was lacking in that department," Alexis said, nodding in agreement.

"The same thing with these parties," Castle went on. "'I'm your biggest fan' 'Where do you get your ideas?'"

"And the ever popular 'Will you sign my chest?'" Alexis added with a disgusted eye roll.

"Yea, that one I don't mind so much," Castle admitted, sipping more champagne.

"Well, FYI; I do," Alexis informed. Her dad didn't respond, instead continuing to stare at his glass. Alexis looked at him contemplation. "Dad?"

"Hmm?"

"Could the reason that you're feeling so predicable is that there's somewhere you'd rather be right now?" the teenager guessed. "Doing something else?" When Castle looked at her in feigned confusion, Alexis smiled knowingly. "Oh, come on Dad! It's okay to admit it. Besides," she lowered her voice, "when you live a double life, one of the two is bound to be boring."

"Okay, we are not talking about _that_ right now," Castle warned. Alexis rose an eyebrow challengingly. "But... if we were... I'd say that you're probably right," he finally conceeded with a sigh.

"A book party's gotta be pretty dull in comparison to a night full of kicking butt and taking names," Alexis acknowledged with a small grin.

"I just wish that for once, someone would come up to me- Richard Castle- and say something new," he admitted.

"Mr. Castle?"

With a sigh, Castle turned around, pen in hand, asking, "Where would ya like it?"

The woman lifted a badge, her eyes amused but her face serious. "Detective Kate Beckett, NYPD. I need to ask you a couple of questions about a murder that took place recently."

Castle was stunned into silence, his daughter mistook the reason why though. As she leaned over to grab his pen and say, "That's new," Alexis believed he was just surprised to be taken for a police investigation. But that was far from the truth. No, Richard Castle, vigilante and world's greatest detective, was surprised because he _knew_ this woman. This was the same detective he saved three years ago after she was poisoned by Scarecrow.

'_This'll be interesting._'

* * *

_**WORLD'S GREATEST DETECTIVE: GENESIS**_

* * *

_"Alison Tisdale... She's dead. Did you ever meet her?"_

_"It's possible," Castle conceeded._

_"What about this guy? Marvin Fisk."_

_"What's this got to do with me?"_

_"Fisk was murdered two weeks ago," Beckett explained. "I didn't put it together until I saw the Tisdale crime scene tonight."_

_"__Flowers for Your Grave__," Castle realized, looking at a photo of the crime scene._

_"And this is how we found Marvin Fisk; right out of __Hell Hath No Fury__."_

"Do any of these 'groupies' send you letters? Disturbing letters?" Beckett wondered. "Because sometimes in cases like these, we find that the killer attempts to-"

"-attempts to contact the subject of his obsession," Castle finished off-handedly, studying the crime scene photos. When he noticed that the detective was silent, he looked up at her. Beckett's eyes were narrowed in question, a surprised look on her face. "I'm uh, well-versed in psychopathic methodologies," Castle explained. "Occupational hazard." _Not just for writing though_, he thought to himself. Realizing that she was still looking at him in consideration, Castle threw the playboy facade up and leaned forward. "Did you know you have beautiful eyes?"

* * *

"So," Alexis asked, following her dad into the study, "are you going to tell me what happened? Or do I have to hack the NYPD database to find out?"

"Hey, we had a deal," Castle reminded. "You can hack whatever you want, but government databases are for _work only_." He stood in front of the bookcase, eyes searching. Alexis waited for his to open the passage to the lair, but he didn't.

"Dad," she began after a few moments, "are you in some kind of trouble?"

"Despite my best efforts, no," Castle assured. "They want my help on a case."

At this, the redhead blinked in surprise. "They want your help? Not the Batman, but you?" she said in wonder. "Why? What case?"

"Someone's been killing people the way I did in my books," Castle explained, pulling two books off of the shelves. "Two vics; Alison Tisdale and Marvin Fisk."

"Are you ok?" Alexis wondered. The writer was silent for a few moments.

"These murders were senseless," he finally stated, "when, usually, murder makes a great deal of sense. Passion, greed, politics... But the killer chose to model after two of my lesser works. Why?"

She knew he was musing to himself, but after nearly three years of working with him in crime-fighting, Alexis learned when to step in. "Come on Dad; it's past bedtime," she stated. "We can figure it out tomorrow."

"Yeah..." His voice was noncomittal, his mind already well into the case.

He had an idea.

* * *

Castle had already been in this office before, but it felt foreign to him. Probably because he was currently mask-less and was speaking without a voice disguiser.

Captain Montgomery entered the office. "Mr. Castle, is it?" he greeted, offering a hand. Castle shook it with a nod. "Captain Montgomery. You said you had useful information about the Tisdale case?"

"Actually, I wanted to offer my services," Castle corrected. "Considering the killer is using scenarios and techniques from my books, I think I could be helpful at finding this guy."

Montgomery considered it, but he shook his head. "I see your point, but we don't normally work with outside help."

At this, Castle snorted. Montgomery fixed him with a glare, to which Castle shrugged helplessly. "I'm sorry, sir, but have you seen the nightlight that the NYPD is so fond of switching on?" he chuckled, knowing full well that it would make the captain more lenient. "Seems to me that the NYPD is used to working with 'outsiders.'"

"Well, the Batman knows what he's doing," Montgomery countered.

"So do I," Castle promised. The captain studied him. "Sir, I can do this. I can help."

The two stared each other down; finally, Montgomery nodded. "Alright Mr. Castle," he conceeded. "You're in." He looked out the office door, motioning to Beckett. The detective walked in.

"Sir?" she greeted.

"Mr. Castle has offered to assist with the Tisdale case."

"Has he now?" Beckett said through gritted teeth.

"It's the least I can do for the city I love," Castle interjected.

"Consider the nature of the crime scenes, I think it's a good idea," Montgomery informed. "He'll be working with you and your team for the remainder of the case."

At this, Beckett's eyes widened, her jaw dropping. "Sir? Could I talk to you for a moment? In private?"

Montgomery looked at her knowingly. "No."

He walked away, leaving Beckett looking gobsmacked and Castle grinning victoriously.

* * *

"Why are you here?" Beckett asked a while later. "You don't care about the victimes, so you're not here for justice-"

_Wrong._

"-you don't care that the guys aping your books, so you aren't here because you're outraged-"

_Partially true._

"-so what is it, Rick?" Beckett wondered. "Are you here to annoy me?" Castle looked down at the papers in front of him.

"I'm here for the story," he ended up saying, deciding to take the safe route. "Why those people? Why those murders?"

"Sometimes there is no story," Beckett countered. "Sometimes the guy's just a psychopath."

Castle shook his head. "There's always a story," he promised. "Like you, for example. Under normal circumstances, you should not be here."

"Really?" Beckett questioned sarcastically. "Then tell me, Mr. Novelist, what is my story? How did I end up here?"

He could do that. He was a story-teller, but he was also a detective. He knew how to pick the clues up, how to piece them together into an intricately woven work of art. He studied her for a moment, preparing to do what he did best; find the story.

"Well, you're not bridge or tunnel," he began. "There's no trace of the boroughs when you talk; that means Manhattan, and _that_ means money... You went to college, a good one too." He leaned forward, continuing to study her. "You had options. Lots of options. More socially acceptable options. Yet here you are."

Beckett nodded in agreement, signaling that so far he was correct. She didn't have to though; Castle already worked out the answer in those few moments.

"Something happened," he deduced. "Not to you; you're wounded, but not that wounded." He shook his head. "It was someone you cared about. Someone you loved." The way Beckett's smile disappeared confirmed Castle's theory. Swallowing roughly, he tried to ignore his own memories of losing someone as he continued. "You probably couldn't live with the thought that the person responsible was never caught." His eyes shifted to her wrist, and he saw it. A man's watch. Why would a woman wear a man's watch? Beckett was not a masculine woman; tough, but still feminine.

_It was her father's, _Castle realized.

Taking in a deep breath, Castle could feel how dangerous this conversation was getting. Clearing his throat, he looked away from her. "And that, Detective Beckett, is why you're here."

"Cute trick," Beckett commented after a few moments. Castle didn't comment on how her voice wasn't as strong as it had been minutes ago as she continued, "But don't think that you know me."

"The point is, is that there's always a story," Castle stated, trying to ignore how soft his own voice had gotten. "You just have to find it."

Beckett looked up from the paper in her hands. "I think I just did."

* * *

"He still isn't speaking; his medical records indicate that he has Pervasive Development Disorder," Beckett informed. referring to Kyle Cabot who was sitting in the interrogation room. "He also has a history of delusions. Guess who his case worker was?"

"Alison Tisdale," Castle realized.

"Yea," Beckett said. "Her file indicates that he was on pretty heavy anti-psychotices."

"Good work Detective Beckett," Montgomery stated.

At this, Castle frowned. "Wait, that's it?" he questioned.

"What more do you want?" Montgomery asked in response. "Evidence is in his apartment and we can connect him with the three victims." He turned to Beckett. "Call Dent and get this guy legal aid."

As Mongtomery walked out of the observation room, Castle shook his head. "That's too easy," he countered.

"Sorry to disappoint you Castle," Beckett shrugged. "But out here, we find someone standing over a body? He's usually the guy who did it." The detective walked away, leaving Castle standing alone staring at Kyle Cabot.

* * *

The very next morning, Beckett was appalled and shocked to find Castle sitting at her desk and sifting through her papers. Rushing over, she snatched the papers out of his hands. "What are you doing?" she demanded.

"Sorry," Castle shrugged, a faint smile on his face. "It's a novelist's habit; going through people's mail, checking their messy cabinets-"

"Why are you still here?" Beckett interrupted. At that, Castle pulled out a wrapped box, offering it to her.

"I just came by to give you this," he responded. "Just something to... memorialize our brief partnership." Beckett looked from the box to the writer, not taking the gift. Castle chuckled, "Don't look so suspicious. Go on; open it."

Uncomfortably, Beckett opened the box, her eyes widening when she saw what was in it.

"I got you an advanced copy," Castle explained, referring to the copy of Storm Fall. "I even signed it to you. Not that you're a fan or anything."

Looking up from the book to its' writer, Beckett held back a smile, her wariness still present. "Thank you, Castle," she said. "This was actually... sweet." Castle smiled and picked up his backpack.

"Well... it was nice to have met you, Detective Beckett." He took a step forward and gently pressed his lips to her cheek. It was a brief peck, but it was long enough for him to drop a listening bug in her pocket. When he pulled back, Beckett's face was one of being taken aback. With a final smile, Castle walked past her and towards the elevator.

The doors closed behind him; that was when he took a bluetooth device out, now able to listen to Beckett and her conversations. He hadn't even reached the bottom floor when he heard her voice: _"He didn't."_ The rustling of paper followed by a gasp of indignation made him grin. _"He did!"_

Walking out of the elevator, Castle gripped the backpack with the police files in it tightly, a smirk on his face. _She was good,_ Castle thought. _Really good._

* * *

_"Richard Castle! You are under arrest for felony theft and obstruction of justice!"_

_"You forgot making you look bad," Castle joked._

_"You know, for a minute there, you made me believe that you were human. Cuff him."_

_"You should know that Kyle Cabot is innocent," Castle called out._

* * *

_"No more interference with this case, Mr. Castle," Montgomery warned. "Do we understand each other?"_

_"Yeah," Castle agreed. "But you've still got the wrong guy."_

* * *

_"The killer had to have known both his intended victim and Kyle Cabot fairly well," Castle mused. "The only victim with any real knowledge about Kyle would have been Alison Tisdale. Somebody wanted her dead. I just have to figure out why."_

* * *

_"He's dying," Castle announced._

_"What makes you think he's dying?"_

_"He's thinner now; sick-thin, not work-out-thin. And kept touching his hair, like he's self-conscious. It's a piece; a good one but new to him. That means chemo is relatively recent; and he was wearing make-up."_

Beckett blinked in surprise. "You noticed all of that in a brief meeting? You barely looked at the guy; you occupied with snooping around the office." Castle shrugged, attempting to appear nonchalant.

"I'm very good with details," he offered. "Did you interview the brother?" Beckett shook her head.

"There was never any reason to," she replied. Castle smiled.

"Now there is."

As he turned and walked away, Beckett stared after him for a moment. Clearly there was more to Richard Castle than she had anticipated. Grinning to herself, she followed him.

* * *

_"Where were you the night of your sister's murder?" Beckett asked._

_"I was out of the country for all three murders."_

"Well, that was a waste of time."

"Don't take it so hard Castle," Beckett chuckled. "After all, you are just a writer."

Castle stopped walking, giving the detective a funny look. "You do realize he was lying, right?" he tested. At Beckett's questioning look, he explained. "He had an alibi prepared and ready to go. He didn't have to think about it. He knew when the other murders took place-" Beckett smirked, making Castle stop. "You already knew that, didn't you?"

Beckett's smirk remained in place. "Innocent people don't prepare alibis."

At this, Castle grinned goofily. "Which means I was right." Beckett groaned and rolled her eyes.

* * *

_"Castle, if you're going in, you should be armed," Beckett warned._

"Thanks Detective, but I don't do guns," Castle rebutted. A frown appeared on Beckett's face. Castle heard a sudden click. He would never admit it, but he hadn't seen it coming; she cuffed him to a scaffolding pole.

"This time," she said, "you stay put."

"Ok, very funny," Castle replied. "Joke's over; let me go."

But the cops were already waking away. Frowning after them, Castle waited until they were out of sight to pull his concealed lock pick from the inside of his sleeve.

_Not bad Detective,_ he thought as he worked the lock. _Not bad at all_.

He made quick work of the cuff; freed, he went around back through the alleyway. Sure that Harrison wasn't making a run for it, Castle headed back to the car. Hearing a sudden thud, however, made him look back. Harrison stood on the ground and Beckett was yelling at him from the top of the fire escape. Without thinking, Castle ran after him.

"Castle, don't!" Beckett yelled, to no avail. She reached the groung, but noth men were out of sigh behind a truck. Slowly and quietly, Beckett crept along the side of the truck, her gun ready to fire-

"-I think you asked him, and he said no. He always said 'no,' didn't he?" Castle's voice asked. Beckett's brow furrowed as she continued walking forward as she continued walking forward. "Self-made man like that, he probably thought you were weak for asking."

"He was the weak one!" Harrison's voice argued. "I was trying to make something of myself, and all he cared about was her!"

"So it wasn't just about the money," Castle said. Beckett finally could see them; Harrison had his gun aimed at Castle, who stood a little more than an arms' length from him. Beckett silently cursed; she didn't have a clear shot without revealing herself. That would put Castle in even more danger. "You wanted to punish him before he died; take away the only thing he ever loved." Castle chuckled. "That actually makes for a really good story."

"Good story- Who are you?!" Harrison demanded, confused by Castle's logic. In a swift movement, Castle closed the distance between himself and the criminal, twisted the gun out of hand, and knocked Harrison unconscious with an elbow to the temple.

"Castle?" Beckett's voice came out as a whisper as she stood from her hiding spot. Castle turned towards her with another goofy grin on his face.

"Tell me you saw that!" he exclaimed.

Manuevering around the truck, Beckett cuffed Harrison before slamming Castle into the brick wall. Ignoring his indignant 'Hey!' she glared at him furiously. "What were you thinking?! You could've gotten yourself killed!"

Castle looked at the gun in his hand, which he handed to her with a knowing grin that surprised her. "The safety was on the whole time."

* * *

_"I guess this is it."_

_"Doesn't have to be. We could go to dinner," Castle offered. "Debrief each other."_

_"So I can be another one of your conquests?" Beckett teased._

_"Or I could be one of yours," the writer played along._

_"It was nice to meet you, Castle."_

_"That's too bad," Castle sighed. "It would've been great."_

_Grinning, Beckett stepped forward to whisper in his ear. "You have no idea."_

* * *

Late night found Batman returning from his nightly patrol. Once he left the Tumbler, he took the mask off and walked over to Alexis. From her seat, the redhead smiled at her dad. "More fun than a book party, right?" she joked. Castle chuckled, coming to stand next to her.

"What did you find out about Harrison?" he asked. Alexis turned to the computer screen.

"According to the NYPD's database, Harrison was booked and will face trial within the month," she informed. With a smiled, she looked at Castle. "So, what was it like? Working within the law and following protocol?"

The vigilante didn't answer right away, which intrigued his daughter. "You know something, Pumpkin?" he finally stated. "It wasn't all that bad."

* * *

"You wanted to see me sir?"

Captain Montgomery looked up as Beckett entered his office. "I just got a call from the Mayor's office," he began. "Apparently, you have a fan."

"A fan?"

"Richard Castle," Montgomery explained. "Seems he's found his main character for his next set of novels; a tough, but savvy female detective."

Beckett blinked in surprise. "I'm... flattered?"

"Don't be," Montgomery chuckled. "He says he has to do 'research.'"

"Oh no."

"Oh yes."

"No way!"

"Beckett-"

"Sir, he is like a nine-year-old on a sugar rush!" Beckett protested. "Incapable of taking _anything_ seriously!"

"But he did help solve this case," Montgomery pointed out. "And based on your report, the man doesn't crack under the pressure of being held a gunpoint."

"But-"

"Let me explain something to you Beckett. When the mayor's happy, the commissioner is happy. And when the commissioner is happy, I'm happy."

Beckett let out a sigh of frustration. Finally, she nodded. "How long, sir?"

Montgomery motioned to something behind her. "It's up to him."

Beckett turned around in surprise; she hadn't even heard him approaching. But there he stood, cocky smile in place and eyes full of victorious pride.

_This is going to be interesting..._

* * *

**And there we go! Castle and Beckett's partnership in the _Knight of the Castle_ series has officially begun!**

**A reminder; not all chapters will be like this. This one was more in-depth due to the fact that it is the pilot episode and has a lot of foundational material in it. Some chapters/episodes will be a single scene, a few selected scenes, a pre-or-post episode scene, and there will also be some original, inspired, or DC related chapters. And not every episode of _Castle _will receive a chapter, just as a side note.**

**So what do you think of this setup? Do you like it? I'm still tweaking with how I have the chapters written out structure-wise, and I am open to suggestions!**

**Thanks for reading. Love you all!**

**Katrina Castillo**


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